This disclosure relates to flat plate membrane bioreactors, and a device used for discharging the bioreactor mixed air and liquid liquor stream into the atmosphere above the liquid surface of the membrane basin.
In the application of flat plate membrane bioreactors, the membranes are aerated with course bubble diffusers to prevent solids accumulation on the outside of the filter surface from slowing the filtration process. Air scouring (bubbling air across the surface of the filters) is used to keep the surface free of solids. Efficient and equal air scouring of each submerged membrane unit is critical to operation. Therefore, air scour flow rates need to be monitored, recorded and controlled. Because equal air scouring is required, the diffusers integral to each submerged membrane unit are kept clean by flushing them with mixed liquor using a unique venturi process. This process is automatically initiated by opening an automated diffuser cleaning valve.
When the automated diffuser cleaning valve is opened, air flows through the diffusers creating a venturi action, which pulls in the liquid mixed liquor through the diffusers. This air/liquid stream flows through the automated Diffuser Cleaning Valve and is deposited into the atmosphere above the liquid surface of the membrane basin.
The deposition of the liquid air stream above the water surface causes splash and spray that is undesirable.